JPH062258B2 - Resin powder coating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention mainly relates to a method for coating parts such as metal or non-metal materials, for example, magnetic materials with powder coating such as thermosetting, and an apparatus used therefor. It is a thing.

<Prior Art> A conventional resin powder coating method for small parts is, for example, as shown in JP-B-51-48168, after the powder coating of the coating object, the coating object is cooled to room temperature. Up to above the powder bath (powder flow chamber) by a combination of elliptical vibration motion, that is, vertical vibration and horizontal vibration, or a spiral gutter U
There is a method of raising the groove and carrying out the object to be coated from the fluid powder interface.

<Problems to be Solved by the Invention> However, since the method described above is performed by the single spot construction method (batch method), the workability is extremely poor, and a hanging tool is used in the flow tank. In order to continue rotation with
A slightly large or heavy object to be coated will have a contact scar on the hanging tool and will have an uneven surface, resulting in variations in moisture resistance and insulation properties. Further, since the object to be coated is taken out from the inside of the fluidized tank after being continuously rotated in the fluidized tank after cooling, the powder body remains on the bottom of the inner surface and the upper portion of the outer surface of the object to be coated. The shape becomes distorted and the film thickness varies.

The conventional method shown above is suitable for thermoplastic resins such as polyamide, but not for epoxy resin powder coating.
Because the epoxy resin powder has a low molecular weight and a low melt viscosity in the initial molten state, and does not have the performance as a coating film as it is, it spends a predetermined temperature and time for crosslinking and curing in three dimensions. However, this method cannot provide a uniform coating thickness and a good coating without pinholes.

There has been a problem to be solved in the resin powder coating process of parts such as magnetic materials. That is, as described above, when the thermoplastic resin powder is used for the coating, the coating is completed and the immersion welding resin powder is molded into a molten film by the energy held by the part, but when the retained heat energy is small, After-cure must be done to cure the melt. Most of the objects to be coated in the present invention belong to this range. When performing after-cure processing, deformed parts, parts with a difference in specific gravity,
Parts with different heat capacities cannot be melted at the same temperature and the same time. In addition, it is difficult to control the temperature and time of the after-cure treatment, which may cause sagging of the film, cracks, pinholes, etc. On the other hand, even in the case of thermosetting resin powder (eg, epoxy resin powder), after cure treatment is basically required.

In this way, no matter which resin powder coating is used, the parts are hung by a hanger or a support like a hanging pin and forcedly heated to several tens of degrees higher than the powder characteristic temperature, and the heating temperature does not drop significantly. Inside, manually or automatically immersed in the powder bath (powder fluidized immersion tank) to complete the coating,
Since after-cure treatment is performed on both the hanger and the hanging pin to perform bake hardening or melting, contact is made, and when the hanger etc. is removed, contact traces remain and it is necessary to correct or re-coat it, resulting in poor productivity. However, the rust prevention, moisture prevention, and insulation effects became unstable, which was a factor that deteriorated the product quality.

<Means for Solving Problems> Therefore, in the present invention, a metal or non-metal material part consisting of the following steps (A) to (F) is provided with a special vibrating feeder, an object to be coated, and a resin powder. The above problems have been solved by developing a resin powder coating method in which continuous multi-parallel simultaneous processing is performed by a combination of a coating device and a belt conveyor that performs a special gelation treatment. That is, the object to be coated consisting of A metal or non-metal material parts in the preheating furnace
A pre-heating step of heating to 100 to 400 ° C., B resin powder is made to flow down, and the heated object to be coated is supplied into the resin powder to be coated, and then the resin powder and the object to be coated are coated. Separate coating process and C coating Place the coated object on a conveyor belt equipped with a cooling device, heat the upper surface of the coated object to melt while moving the lower surface of the coated object in a cooled state, and gel the resin on the upper surface side. A first gelling step of: D, a gelling surface of the article to be coated is turned down, a non-gelled surface is turned up, and a plurality of articles to be coated are fed in parallel; The second gelling step in which the upper part of the article to be coated is heated and melted to gelate the entire resin while being placed upside down and moving on the conveyor belt of 100 to 300 ℃
It is composed of various curing steps of heating and curing at.

The following device has been newly developed as a device capable of performing such a process. It is provided with a resin powder flow supply path (18) at the lower end of a hopper (2) having a cyclone (1) above, which is suitable for the coating step (B), and the resin powder flow supply path (18).
A coating chute (4) is provided on the side surface, and the lower side is opened and the flow cutting surface of the vibrating feeder (5) is below the powder cutting perforated plate (7) followed by the air jet perforated plate (6). ), And here, another powder cutting perforated plate is provided, and the resin powder receiving hopper (8) and the powder supply tank are provided below these powder cutting perforated plates (7).
(9) is provided, and the resin powder coating apparatus characterized in that the injector (10) and the transfer hose (11) are connected between the powder supply tank (9) and the cyclone (1). . The powder cutting perforated plate (7) may be provided before or after either or both of the air ejection perforated plate (6), and the arrangement and the size of the holes may be the size and shape of the object to be processed, the film thickness. Set to meet various conditions such as.

Furthermore, the following apparatus used in the first gelation step and the second gelation step of the next step was developed. That is, a gelling zone (14) having a cooling device (12) on the lower surface side and a heating device (13) on the upper surface side, and a cooling zone (15) having only the cooling device (12) on the lower surface side are provided. A metal or a metallization comprising a belt conveyor for forming a circulation system of a steel belt (17) having a release layer (16) on the surface of these gelation zone (14) and cooling zone (15). It is a device for gelling a resin powder coating layer of a non-metal material part.

<Operation> According to the method and apparatus of the present invention, the object to be coated such as a metal or non-metal material is brought to a temperature at which the resin powder can be attached in the preheating step, and the powder evenly attached to this in the coating step. The body resin is cured only in the first gelation step by forced cooling from the bottom, and only the top of the article to be heated is cured, and then the article to be coated is inverted, and in the next second gelation step, the article to be coated is In the first gelation step, the lower portion is heat-cured to form a coating film without sagging on the whole.
By these steps and devices, a substantially uniform resin film is formed on the object to be coated.

<Example> An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic plan view of an apparatus suitable for the method of the present invention.
FIG. 2 is a perspective view of an automatic resin powder coating device. FIG. 3 is a vertical cross-sectional view of the relevant part. FIG. 4 is a partially cutaway side view of the resin powder coating layer gelling apparatus, and FIG. 5 is a sectional view taken along line XX in FIG. FIG. 6 is a view showing a state of coating an object to be coated by the method of the present invention. FIG. 7 is a diagram showing a state of coating an object to be coated by a conventional method.

As is apparent from these figures, the present invention
It is a resin powder coating method in which metal or non-metal material parts are continuously and simultaneously processed in a multi-parallel manner by a combination of a vibrating feeder and a belt conveyor from the steps (A) to (F). That is, as shown in FIG. 1, the apparatus is provided with a preheating furnace (21) following the supply part (20) of the object to be coated with the ferrite core, and the object to be coated is placed on the belt (22). To move. In the preheating furnace (21), the article to be coated was heated at 200 ° C. for 10 minutes (heating step (A)).

Then, next, the resin powder is allowed to flow down, and after the heated object to be coated is supplied into the flowing resin powder for coating,
The coating step (B) is to separate the resin powder and the article to be coated. Details of the equipment used for this process can be found in FIG. The device is a cyclone that separates resin powder and carrier gas upward.
It has (1) and a hopper (2) is provided below it. A resin powder flow supply path (18) is provided at the lower end of the hopper (2). On the side surface of the resin powder flow supply path (18), the object to be coated
The supply chute (4) of (3) is provided, and the vibrating feeder (5) is provided with the lower part opened. Its vibrating feeder (5)
As shown in FIG. 3, a first powder cutting perforated plate (7), an air jetting perforated plate (6) and a second powder cutting perforated plate (7) are provided in this order on the flow channel surface. A resin powder receiving hopper (8) and a powder supply tank (9) are provided below the powder cutting porous plate (7), and an injector (10) is provided between the powder supply tank (9) and the cyclone (1). And the transfer hose (11).

The object to be coated (3) to which the resin powder has adhered through the above steps is placed on a conveyor belt (17) with a cooling device and heated and melted at 200 ° C for 15 minutes on the upper part of the object to be moved while moving. It transferred to the 1st gelation process (C) which gels an upper side resin.

Details of the first gelling furnace (24) in which this step is carried out can be seen in FIGS. 4 and 5. The apparatus is provided with a gelling zone (14) having a cooling device (12) on the lower surface side and a heating device (13) on the upper surface side, and a cooling zone (15) having only the cooling device (12) on the lower surface side. Has been. The cooling device (12) is a forced water cooling system having a nozzle. The heating device (13) has a structure including an upper sirocco fan, a heater, and a lower outlet. The object to be coated (3) is these cooling device (12) and heating device (13).
Placed on a steel belt (17) that is stretched in an endless state between and a release layer (16) of Teflon film is formed on the surface,
The lower part is cooled and the upper part moves while being heated to 150 ° C. The article to be coated (3) whose upper part is heated only gels in that part, and the lower part remains unheated, and the cooling device (12) is placed on the lower surface side.
The overall temperature is lowered in the cooling zone (15) in which only one is arranged.

Next, by the reversing sorting and conveying device (27) or manually, the gelling surface of the coating object is turned down, the non-gelled surface is turned upside and the coating material reversing step of supplying a plurality of coating materials in parallel ( D).
By this step, the article to be coated (3) is inverted on the conveyor belt with the cooling device.

Furthermore, the second gelling step (E) is performed in which the upper part of the article to be coated is heated and melted at 200 ° C. for 15 minutes while moving to gel the entire resin. This is the fourth gel used in the first gelation step (C).
It was treated in a second gelling furnace (25) similar to that shown in FIGS.

Finally, the article to be gelled with the resin coating layer was cured by heating in a curing oven (26) at 150 ° C. for 30 minutes, and then cooled to obtain a product. The cut end faces of the article to be coated (3) in each step of the present invention are shown in FIG. For comparison, FIG. 7 shows the same cut end face in the conventional process. As you can see by comparing these,
Although the coating film of the product obtained by the conventional method has unevenness in thickness, the product obtained by carrying out the present invention is good in that no uneven surface is observed.

<Effects of the Invention> With the completion of the present invention, it has become possible to perform good resin powder coating mainly on parts such as metal or non-metal materials, which are excellent in rust-prevention, moisture-proof, and insulating effects. In particular, by completing the non-contact coating process that does not use hangers etc., the work of repairing contact scars, which was conventionally required, is unnecessary, so the processing efficiency can be greatly improved and high quality products can be provided. became. In addition, productivity was dramatically improved by enabling continuous multi-parallel simultaneous processing.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an apparatus suitable for the method of the present invention.
FIG. 2 is a perspective view of the resin powder coating device. FIG. 3 is a vertical cross-sectional view of the relevant part. FIG. 4 is a partially cutaway side view of the resin powder coating layer gelling apparatus used in the process, and FIG. 5 is a sectional view taken along line XX in FIG. FIG. 6 is a view showing a state of coating an object to be coated by the method of the present invention. FIG. 7 is a diagram showing a state of coating an object to be coated by a conventional method. (1) Cyclone (2) Hopper (3) Object to be coated (4) Supply chute (5) Vibration feeder (6) Air jetting perforated plate (7) Slicing perforated plate (8) Resin powder receiving hopper (9) Powder Body supply tank (10) Injector (11) Transfer hose (12) Cooling device (13) Heating device (14) Gelation zone (15) Cooling zone (16) Release layer (17) Belt (18) Resin powder flow Supply path (20) Supply section (21) Pre-heating furnace (22) Belt (24) First gelling furnace (25) Second gelling furnace (26) Cure furnace (27) Reverse sorting and conveying device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Hara 107-39 Higashihachibanban, Sendai-shi, Miyagi No.1403 Parsity Sendai 1403 (72) Inventor Kenji Sasaki 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo (Hibiya International Building) Kawatetsu Techno Research Co., Ltd. (56) References JP-A-63-54974 (JP, A)

Claims (3)

[Claims] 1. A resin powder coating method for continuously and simultaneously processing a metal or non-metal material part comprising the following steps (A) to (F) with a combination of a vibrating feeder and a belt conveyor, A metal or Pre-heating furnace for coated objects made of non-metallic material parts
A pre-heating step of heating to 100 to 400 ° C., B resin powder is made to flow down, and the heated object to be coated is supplied into the resin powder to be coated, and then the resin powder and the object to be coated are coated. The coating step of separating into C and C is placed on a conveyor belt with a cooling device, and while the lower surface of the coated object is moved in a cooling state, the upper surface of the coated object is heated and melted to be the upper surface side. A first gelling step of gelling the resin; and a coated article reversal step of reversing the gelled surface of the coated article downward and the ungelled surface upward and supplying a plurality of coated articles in parallel. E The second gelling step of placing the article to be coated on the conveyor belt with the cooling device in reverse, and heating and melting the upper portion of the article to be gelled while moving, and the F resin coating layer is a gel. 100-300 ℃
Curing process of curing by heating and cooling. 2. A hopper (2) having a cyclone (1) above it
The resin powder flow supply path (18) is provided at the lower end of the, and the supply chute (4) for the article to be coated (3) is provided on the side surface of the resin powder flow supply path (18), and the lower side is opened to the lower side. Vibrating feeder (5)
And a powder cutting perforated plate on the flow path surface of the vibrating feeder (5).
(7) is followed by an air jet porous plate (6), and the powder cutting porous plate
(7) A resin powder receiving hopper (8) and a powder supply tank (9) are provided below, and an injector (10) and a transfer hose (11) are provided between the powder supply tank (9) and the cyclone (1). ) And a resin powder coating device. 3. A cooling device (12) on the lower surface side and a heating device on the upper surface side.
The gelation zone (14) in which (13) is arranged and the cooling device (1
A cooling zone (15) having only 2) is provided, and a release layer (1) is formed on the surface of these gelation zone (14) and cooling zone (15).
A gelling apparatus for a resin powder coating, comprising a belt conveyor forming a circulation system of a steel belt (17) having 6).